Shares of beleaguered retailer J.C. Penney are up more than 6 percent in aftermarket trading on Thursday after billionaire financier George Soros disclosed a 7.9 percent stake in the company.

Soros disclosed he owns about 17.4 million shares of the Plano, Texas, department store operator in a filing with the Securities and Exchange Commission. The SEC requires shareholders to disclose stakes of 5 percent or more in a company.

Shares are up 98 cents, or 6.4 percent, to $16.22 in aftermarket trading, after ending 5 cents higher at $15.24.

J.C. Penney earlier this month fired its CEO, Ron Johnson, after 17 months on the job and rehired his predecessor Mike Ullman. An ambitious turnaround plan by Johnson backfired and caused sales to plummet.